1. Technical Field
The present invention relates a piezoelectric actuator, a liquid ejecting head, and a method of manufacturing a piezoelectric actuator.
2. Related Art
In a piezoelectric element that is used in an ink jet type recording head that is known as a representative example of a piezoelectric actuator, and the like, it is demanded for a crystal system thereof to be oriented in a (100) face in a rhombohedral crystal so as to actually raise piezoelectric characteristics of a piezoelectric layer. In addition, a method of manufacturing a piezoelectric element is disclosed (for example, refer to JP-A-2011-238774). In the method, a piezoelectric layer composed of lead zircornate titanate (PZT) is formed on a lower electrode through a lead titanate layer in order for the lead zircornate titanate to be preferentially oriented to the (100) face. In addition, a technology, in which a lanthanum nickel oxide (LNO) is used as a seed layer, and a bismuth ferrate-based and bismuth titanate-based piezoelectric layer is preferentially oriented to the (100) face, is disclosed (for example, refer to JP-A-2012-006182). In addition, a buffer layer, which is constituted by a metal element capable of forming a B site of a PZT crystal, is preferentially oriented to the (100) face as a seed layer, is also suggested (for example, refer to JP-A-2005-340428).
However, when manufacturing ink jet type recording head, the piezoelectric layer is also formed on an insulator layer that becomes a nonactive portion in addition to a lower electrode that becomes an active portion, but the piezoelectric layer may not be effectively oriented due to an influence by the base. In addition, there is a problem that fluctuation in the orientation occurs at a boundary between the active portion and the nonactive portion, and thus a degree of orientation locally decreases. Such a decrease in the degree of orientation causes a decrease in an amount of displacement and occurrence of cracks.
In addition, the problem exists not only in the ink jet type recording head but also in other liquid ejecting head that ejects liquid droplets other than ink. In addition, the problem also exists in a piezoelectric element or a piezoelectric actuator which is used in devices other than the liquid ejecting heads.